Go to someone like Fasthosts and register a domain of your choice, it usually costs in the region of £10 a year or so for something like V6Driver.co.uk (purely for illustration, I'm not suggesting this as a domain name). Your new ISP will almost certainly offer a similar service, but the biggies (BT, Virgin, TalkTalk etc) tend to be way overpriced compared to the smaller outfits
Then you can either buy email services from them too, or you can set up a redirect so that timbo@V6Driver.co.uk gets redirected to your existing ISP account Johnv6@talktalk.com or whatever.
I use Fasthosts purely because I prefer to do business locally, and they are based in Gloucester. I've been with them for 15 years or so and they're fine, but I'm sure there will be somebody local to you offering a similar service.
